10/12/17
AIM
Section 3. Distress and Urgency Procedures
6-3-1. Distress and Urgency
Communications
a. A pilot who encounters a distress or urgency
condition can obtain assistance simply by contacting
the air traffic facility or other agency in whose area of
responsibility the aircraft is operating, stating the
nature of the difficulty, pilot"s intentions and
assistance desired. Distress and urgency communications procedures are prescribed by the International
Civil Aviation Organization (ICAO), however, and
have decided advantages over the informal procedure
described above.
b. Distress and urgency communications procedures discussed in the following paragraphs relate to
the use of air ground voice communications.
c. The initial communication, and if considered
necessary, any subsequent transmissions by an
aircraft in distress should begin with the signal
MAYDAY, preferably repeated three times. The
signal PAN-PAN should be used in the same manner
for an urgency condition.
d. Distress communications have absolute priority
over all other communications, and the word
MAYDAY commands radio silence on the frequency
in use. Urgency communications have priority over
all other communications except distress, and the
word PAN-PAN warns other stations not to interfere
with urgency transmissions.
e. Normally, the station addressed will be the
air traffic facility or other agency providing air traffic
services, on the frequency in use at the time. If the
pilot is not communicating and receiving services,
the station to be called will normally be the air traffic
facility or other agency in whose area of responsibility the aircraft is operating, on the appropriate
assigned frequency. If the station addressed does not
respond, or if time or the situation dictates, the
distress or urgency message may be broadcast, or a
collect call may be used, addressing "Any Station
(Tower)(Radio)(Radar)."
f. The station addressed should immediately
acknowledge a distress or urgency message, provide
assistance, coordinate and direct the activities of
assisting facilities, and alert the appropriate search
Distress and Urgency Procedures
and rescue coordinator if warranted. Responsibility
will be transferred to another station only if better
handling will result.
g. All other stations, aircraft and ground, will
continue to listen until it is evident that assistance is
being provided. If any station becomes aware that the
station being called either has not received a distress
or urgency message, or cannot communicate with the
aircraft in difficulty, it will attempt to contact the
aircraft and provide assistance.
h. Although the frequency in use or other
frequencies assigned by ATC are preferable, the
following emergency frequencies can be used for
distress or urgency communications, if necessary or
desirable:
121.5 MHz and 243.0 MHz. Both have a range
generally limited to line of sight. 121.5 MHz is
guarded by direction finding stations and some
military and civil aircraft. 243.0 MHz is guarded by
military aircraft. Both 121.5 MHz and 243.0 MHz are
guarded by military towers, most civil towers, and
radar facilities. Normally ARTCC emergency
frequency capability does not extend to radar
coverage limits. If an ARTCC does not respond when
called on 121.5 MHz or 243.0 MHz, call the nearest
tower.
6-3-2. Obtaining Emergency Assistance
a. A pilot in any distress or urgency condition
should immediately take the following action, not
necessarily in the order listed, to obtain assistance:
1. Climb, if possible, for improved communications, and better radar and direction finding detection.
However, it must be understood that unauthorized
climb or descent under IFR conditions within
controlled airspace is prohibited, except as permitted
by 14 CFR Section 91.3(b).
2. If equipped with a radar beacon transponder
(civil) or IFF/SIF (military):
(a) Continue squawking assigned Mode A/3
discrete code/VFR code and Mode C altitude
encoding when in radio contact with an air traffic
facility or other agency providing air traffic services,
unless instructed to do otherwise.
6-3-1